<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Document</title>
</head>
<body>
  <h1>first</h1>
  <a href="second.html">second</a>

  <input type="button" value="前进" id="btn2">
  <script>
    var btn2 = document.getElementById('btn2');
    btn2.onclick = function () {
      // history  历史
      // window.history
      // history.forward();
      history.go(1);
    }
  </script>
</body>
</html>
